142 THE AUDITORY NERVE AND COCHLEA, BY W. WALDEYER. 



ments may also be compared with those of Reichert (44, 45). 

 The researches of Schwalbe (71) have satisfactorily shown that 

 the scalse correspond to a lymphatic cavity, or still more closely 

 to the perichorioideal space of the bulbus oculi, or to the arach- 

 noideal space of the brain. (See also the statements of Kolliker, 

 62, 34.) 



The membrane of the fenestra rotunda belongs both to the 

 mucous membrane of the tympanic cavity, and to the perios- 

 teum of the cochlea; and, in accordance with this, presents 

 two layers composed of finely fibrillar connective tissue. The 

 tympanal layer is the thicker of the two, is traversed by 

 numerous vessels, and is invested with the epithelium of the 

 tympanic cavity ; the vestibular layer looking towards the 

 corresponding scala is directly continuous with the periosteum 

 of the first turn of the cochlea. 



Brief allusion may be here made to the aquceductus cochlece, 

 which as is generally admitted (see especially the account 

 given by Hensen, 27, and Henle, 26) conveys only a fibrous 

 process of the dura mater, and a vessel running to the vena 

 jugularis interna. The opening of the aquseductus is close to 

 the commencement of the scala tympani. 



In proceeding to the description of the principal portion of 

 the cochlea, the ductus cochlearis, we may first take a bird's- 

 eye view of its constituent parts as exhibited in such transverse 

 sections as figs. 321 and 322. 



In addition to what has already been stated on p. 134, in 

 regard to the position, form, arid boundaries of the ductus, I 

 may state in the first place that the vestibular wall, or mem- 

 brane of Reissner, is inserted externally to the semiluriar 

 cushion of connective tissue (e e). The point of attachment, 

 angulus vestibularis (JRi), is marked by a slight projection 

 (Henle). The external point of attachment of the tympanal 

 wall (H L sp) is formed by a strong process, triangular in 

 section, termed the ligamenturfi spirale (L sp). Between the 

 two processes is the outer wall of the duct, in which we may 

 recognize the vascular stria vascularis (St v), as well as a third 

 small elevation, the ligamentum spirale accessorium (L sp a), 

 with a vessel, the vas prominens of Henle, forming the tym- 

 limit of -the stria ; arid lastly, situated between this eleva- 



